Trends in care by nonphysician clinicians in the United States.

BACKGROUND: The 1990s saw rising numbers of graduates of training programs for nonphysician clinicians, passage of legislation expanding their scope of practice, and a proliferation of managed-care models that emphasized the use of these providers as a strategy for containing health care costs. METHODS: We used two nationally representative surveys to examine trends in outpatient care provided by physicians and nonphysician clinicians between 1987 and 1997, adjusting for the case mix. Analyses examined care provided by 10 categories of nonphysician clinicians: chiropractors, midwives, nurses or nurse practitioners, optometrists, podiatrists, physician assistants, physical or occupational therapists, psychologists, social workers, and others. RESULTS: Between 1987 and 1997, the proportion of patients who saw a nonphysician clinician rose from 30.6 percent to 36.1 percent (adjusted relative risk for 1997 as compared with 1987, 1.42 [95 percent confidence interval, 1.35 to 1.50]). The trend was driven by an increase in the proportion of persons who visited both a physician and a nonphysician clinician (from 23.5 percent to 30.9 percent; adjusted relative risk, 1.49 [95 percent confidence interval, 1.40 to 1.58]), rather than an increase in the proportion who saw only a nonphysician clinician (from 7.2 percent to 5.3 percent; adjusted relative risk, 0.81 [95 percent confidence interval, 0.70 to 0.93]). This pattern was consistent in analyses of specific medical conditions and specific types of nonphysician clinicians. There was an increase in the proportion of patients obtaining preventive services from nonphysician clinicians and a decline in the proportion receiving acute care services from such clinicians. CONCLUSIONS: From 1987 to 1997, there was a degree of differentiation between physicians and nonphysician clinicians with respect to the services they provided but not with respect to the patients they treated. The implications of these findings hinge on the degree to which the increase in conjoint service delivery represents growing coordination or fragmentation of care.